Central Administration

Select the site collection which should be read-only and select the “Read-Only” radio button. Click OK.

Now, browse the site collection and we can see a message on the top saying, “This site is read-only at the farm administrator’s request”.

Go to any document library or list. The options like New document, Upload document, New Folder, Edit document, Check out or in, Delete document or edit properties will be disabled. The user can only view the document or download a copy of it.

Database

Select the content database and go to its Properties.

Click on Options menu from the left-hand side of the window and under the “State” section, set “Database Read-Only” to “True”, as shown in the image below.

Now, the content database is in read-only mode.

Browse any site collection that exists in the content database and you will see a message on the top that says, “We apologize for any inconvenience but we’ve made the site read-only while we are making some improvements”.

Go to any document library or list. Options like New document, Upload document, New Folder, edit document, Check out or in, Delete document or edit properties will be disabled. The users can only view the document or download a copy of it.